(Unicode C++) Download Photo to a File

Assuming we have the ID of a Photo, this example demonstrates how to download the photo image data to a file.

Chilkat C/C++ Library Downloads
MS Visual C/C++ Linux/CentOS C/C++ Alpine Linux C/C++ MAC OS X C/C++	armhf/aarch64 C/C++ C++ Builder iOS C/C++ Android C/C++	Solaris C/C++ MinGW C/C++

#include <CkOAuth2W.h>
#include <CkRestW.h>
#include <CkStringBuilderW.h>
#include <CkJsonObjectW.h>
#include <CkHttpW.h>

void ChilkatSample(void)
    {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // This example assumes a previously obtained an access token
    CkOAuth2W oauth2;
    oauth2.put_AccessToken(L"FACEBOOK-ACCESS-TOKEN");

    CkRestW rest;

    // Connect to Facebook...
    bool success = rest.Connect(L"graph.facebook.com",443,true,true);
    if (success != true) {
        wprintf(L"%s\n",rest.lastErrorText());
        return;
    }

    // Provide the authentication credentials (i.e. the access key)
    rest.SetAuthOAuth2(oauth2);

    // Assumes we've already obtained a Photo ID.
    const wchar_t *photoId = L"10210199026347451";

    CkStringBuilderW sbPath;
    sbPath.Append(L"/v2.7/");
    sbPath.Append(photoId);

    // First we're going to get the photo informaton so we can get the URL of the image file data.
    // Select the fields we want.
    // See https://developers.facebook.com/docs/graph-api/reference/photo/
    rest.AddQueryParam(L"fields",L"id,album,images");

    const wchar_t *responseJson = rest.fullRequestNoBody(L"GET",sbPath.getAsString());
    if (rest.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",rest.lastErrorText());
        return;
    }

    CkJsonObjectW json;
    json.put_EmitCompact(false);
    json.Load(responseJson);

    // Show the JSON in human-readable format.
    wprintf(L"%s\n",json.emit());

    // Get the image URL.
    const wchar_t *imageUrl = json.stringOf(L"images[0].source");
    wprintf(L"Downloading from %s\n",imageUrl);

    CkStringBuilderW sbImageUrl;
    sbImageUrl.Append(imageUrl);

    // Build the output local file path.
    CkStringBuilderW sbToPath;
    sbToPath.Append(L"qa_output/fb");
    sbToPath.Append(json.stringOf(L"id"));
    bool bCaseSensitive = false;
    if (sbImageUrl.Contains(L".jpg",bCaseSensitive) == true) {
        sbToPath.Append(L".jpg");
    }
    else {
        sbToPath.Append(L".png");
    }

    wprintf(L"Downloading to %s\n",sbToPath.getAsString());

    // Download using Chilkat HTTP.
    CkHttpW http;
    success = http.Download(imageUrl,sbToPath.getAsString());
    if (success != true) {
        wprintf(L"%s\n",http.lastErrorText());
    }
    else {
        wprintf(L"Downloaded.\n");
    }
    }